Telephone line state detecting device

ABSTRACT

A telephone line state detecting device that is connectedly provided with a hardware detecting circuit when a telephone line is connected to a modem. The hardware detecting circuit is connected to a processing unit such that, in use, the hardware detecting circuit can detect pulses generated by voltages flowing through the telephone line. The pulses are being processed by the processing unit to judge whether the telephone is disconnected or the electrical contact thereof is deficient, or whether the telecommunications equipment used in conjunction therewith is busy or not in use.

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention relates to a telephone line state detecting devicethat primarily detects whether a telephone line is generating pulses todetermine whether the telephone line is disconnected or the electricalcontact thereof is poor, or whether the telecommunications equipmentused in conjunction therewith is busy or not in use.

(b) Description of the Prior Art:

The major function of a telephone line is to convert signals and toenable the user to communicate with the outside. However, theconventional telephone line in general can only let the user knowwhether a telephone call is successfully connected. The user is unableto know the state of the telephone line or the use status thereof.

SUMMARY OF THE INVENTION

A primary object of the present invention is to provide a telephone linestate detecting device that includes a hardware detecting circuitprovided in a telephone line connected to a modem. The hardwaredetecting circuit is connected to a processing unit. In use, thehardware detecting circuit detects pulses generated by voltages flowingthrough the telephone line, which are processed by the processing unitto determine whether the line is interrupted or electrical contactthereof is poor, or whether the telecommunication equipment used inconjunction therewith is busy or not in use.

Another object of the present invention is to provide a telephone linestate detecting device that includes a processing unit provided with aROM for storing relevant data. After processing the pulses generated bythe voltages flowing through the telephone line, the processing unitcan, based upon the data stored in the ROM, determine whether or not toactuate the hardware detecting circuit.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features and advantages of the present inventionwill be more clearly understood from the following detailed descriptionand the accompanying drawings, in which,

FIG. 1 is a schematic view of the circuitry of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to FIG. 1, a telephone line state detecting deviceaccording to the present invention is a device that utilizes the pulsesemitted by a telephone line to judge the state of use of the telephoneline. The device is provided with a hardware detecting circuit 10, whichis provided with a first counter-amplifier 11. The firstcounter-amplifier 11 has a first leg 111 connected to a signal line of amodem 100. In this embodiment, the telephone line is a DAA 2000 seriesone. The first counter-amplifier 11 has a third leg 113 connectedlyprovided on a first leg 121 of a second counter-amplifier 12. The secondcounter-amplifier 12 has a third leg 123 connected to two resistors 13that are connected in parallel. One of the resistors 13 is connected inseries to a capacitor 15. The capacitor 15 has an output end connectedto an output end of an algorithm amplifier 14, and the output end of thecapacitor 15 is connected to a first gate 16. The first gate 16 has anoutput end connected to a second gate 17. The second gate 17 has anoutput end connected to a display circuit 30. The display circuit 30 isadapted to display detection results obtained via the hardware detectingcircuit 10. The display circuit 30 may be a diode or a display screen.

Furthermore, the first counter-amplifier 11 has a second leg 112connected to a processing unit 20. The processing unit 20 is providedwith a CPU 21 for processing and making judgments, and is connected to aROM 22 and a RAM 23. The ROM 22 has stored therein frequency settingvalues and relevant data.

Referring again to FIG. 1, when the modem 100 is connected to acommunications equipment, such as a telephone set, the CPU 21 of theprocessing unit 20 can judge whether the modem 100 in use based upon thefrequency generated by the telephone line. If the modem 100 is not inuse, the CPU 21 of the processing unit 20 will calculate the frequency(DM 207.23 in this embodiment) in the modem 100, and store the same inthe RAM 23. At the same time, the data relevant to the frequency settingvalues stored in the ROM 22 are retrieved and judged. When the signalfrequency is greater than the set value, the hardware detecting circuit10 will be actuated. When the signal frequency is smaller than the setvalue, the hardware detecting circuit 10 will be closed. In addition,when the signal frequency is less than “0”, the hardware detectingcircuit 10 will be closed, and the modem 100 will be triggered to emitpulse signals.

When the hardware detecting circuit 10 is actuated, the first and secondcounter-amplifiers 11, 12 are controllable to actuate or close acharging circuit consisting of the resistors 13, the algorithm amplifier14, and the capacitor 15. Furthermore, the first leg 111 of the firstcounter-amplifier 11 is adapted to receive pulse signals generated bythe modem 100, whereas the second leg 112 thereof is adapted to actuateor close the pulse signals generated by the modem 100. In other words,when the potential of the second leg 112 of the first counter-amplifier11 is high, it receives pulse signals generated by the modem 100. On thecontrary, when the potential of the second leg 112 is low, reception ofthe pulse signals generated by the modem 100 is stopped. Furthermore,when a pulse passes through the third leg 123 of the secondcounter-amplifier 12, charging will quickly proceed by means of theresistors 13 and capacitor 15 that are connected therewith, causing thepotential of the output end of the second gate 17 to be high in a shortwhile. And after passage of the pulse, i.e., when the potential of thesecond leg 112 of the first counter-amplifier 11 is low, the capacitor15 will gradually discharge through the resistors 13 connected thereto.Low potential indicates that the telephone that is connected to themodem 100 is currently used by other equipment, or that the electricalconnection is poor. High potential indicates that the telephone that isconnected to the modem 100 is currently not connected with any otherequipment. As for the existence of pulses, it indicates interventionfrom other equipment.

Although the present invention has been illustrated and described withreference to the preferred embodiment thereof, it should be understoodthat it is in no way limited to the details of such embodiment but iscapable of numerous modifications within the scope of the appendedclaims.

What is claimed is:
 1. A telephone line state detecting device, thatutilizes pulses generated by a telephone line to judge use state of saidtelephone line, said device being provided with a hardware detectingcircuit, said hardware detecting circuit being provided with a firstcounter-amplifier, said first counter-amplifier having a first legconnected to a signal line of said telephone line, a second legconnected to a processing unit, and a third leg connected to a first legof a second counter-amplifier, said second counter-amplifier having athird leg connected to parallel resistors, one of said resistors beingconnected in series to an algorithm amplifier, the other of saidresistors being connected in series to a capacitor, said capacitorhaving an output end connected to an output end of said algorithmamplifier, said output end of said capacitor being connected to a firstcounter-gate, said first counter-gate having an output end connected toa second counter-gate, said second counter-gate having an output endconnected to a display circuit that can display detection results. 2.The telephone line state detecting device as defined in claim 1, whereinsaid processing unit includes a CPU for purposes of judgment, a ROM forstoring frequency setting values and relevant data, and a RAM fortemporary storage of data.
 3. The telephone line state detecting deviceas defined in claim 1, wherein said display circuit is a diode.
 4. Thetelephone line state detecting device as defined in claim 1, whereindisplay circuit is a display screen.